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the genus. The-Alpine Marmot, A. marmotta, is familiar to most
persons. The animal lives high up in the Alps, and when
danger threatens it gives vent to a shrill whistle. It hibernates
in the winter, and as many as ten to fifteen animals may be found
closely packed together in a single, carefully-lined burrow.

The only other European species is A. ~bobac, the Siberian
MaTmot, which occurs in the extreme east of Europe, and is
also Asiatic. There are four ISTorth American species, including
the Quebec Marmot, A. monax.

The genus Pteromys (of which  the proper name, antedating

FIG. 234.

Ptevomys by five years, appears to be Petaurista) is confined to the
Oriental region, where there are a dozen species or so. The
limbs are united "by a parachute extending to the toes, and sup-
ported anteriorly by a cartilage attached to the wrists. There
are also membranes anteriorly uniting the fore-limbs to the neck,
and posteriorly uniting the hind-limbs to the root of the tail and
a trifle beyond. The skull and the dental formula are as in
Sciurus, but the pattern of the molars, which is much complicated,
seems to argue a different mode of nutrition. There are twelve
pairs of ribs* The large intestine (in P. petawrista) is very nearly
as long as the small, and the caecum is also " colossal"; the
measurements in an individual of the species named were: small
intestine, 670 mm.; caecum, 320 mm.; large intestine, 650 mm,